Oil Pump for Vehicle

ABSTRACT

A hydraulic pump for a vehicle includes a pump housing, an inlet port formed to the pump housing, a chain cover combined with the pump housing and forming an outlet port with the pump housing, and a rotor provided between the pump housing and the chain cover and having a predetermined thickness, the rotor including an inner gear and an outer gear. The outlet port includes a center port having the same thickness as the rotor, a housing port formed to the pump housing and having a first depth and a cover port formed to the chain cover and having a second depth, and a sum of the first depth and the second depth is 50% to 60% of the thickness of the rotor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2020-0058945, filed in the Korean Intellectual Property Office on May18, 2020, which application is hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a hydraulic pump for a vehicle.

BACKGROUND

A general hydraulic pump is supplied with oil from an oil pan through aninlet port and generates high-pressure oil through rotation of a rotorand exhausts it through an outlet port.

The oil pressure of the periodic pulsating waveform is formed on theoutlet port of the hydraulic pump by the hydraulic pump rotating at highspeed and high pressure. Noise occurs due to the pulsating pressurecomponent, and this is called high-speed noise (whine noise).

The noise generated by the hydraulic pump affects even the vehicleinterior through a chain cover adjacent to the hydraulic pump.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention, andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY

The present invention relates to a hydraulic pump for a vehicle.Particular embodiments relate to a hydraulic pump for a vehicle capableof reducing whine noise by reducing pulsation pressure.

Embodiments of the present invention provide a hydraulic pump for avehicle capable of reducing whine noise through reduction of pulsationpressure.

A hydraulic pump for a vehicle according to an exemplary embodiment ofthe present invention may include a pump housing of which an inlet portis formed thereto, a chain cover combined with the pump housing andforming an outlet port with the pump housing, and a rotor including aninner gear and an outer gear, provided between the pump housing and thechain cover, and having a predetermined thickness and wherein the outletport includes a center port having the same thickness of the rotor, ahousing port formed to the pump housing and having a first depth and acover port formed to the chain cover and having a second depth, andwherein the sum of the first depth and the second depth is 50% to 60% ofthe rotor thickness.

The ratio of the first depth and the second depth may be 2:1 to 3:1.

The outlet port may be formed inclined in the direction of the inletport at the end.

The inner gear and the outer gear may form a plurality of pockets, anotch that communicates with the outlet port may be formed in the pumphousing, and the formation position of the notch may be the anglecorresponding to the one pocket from the inlet port toward the outletport and a position that is 5 degrees to 10 degrees apart based on thecenter of the rotor.

An end of the outlet port may be formed at 100 degrees to 120 degreesfrom the formation position of the notch based on the center of therotor.

A length of the notch may be lo degrees to 15 degrees from the formationposition of the notch, based on the center of the rotor.

A depth of the notch may be 2% to 5% of the rotor thickness.

A slope may be formed between the end of the notch and the outlet portand the slope may be is formed in a 30 degree to 60 degree angle.

A hydraulic pump for a vehicle according to an exemplary embodiment ofthe present invention may include a pump housing of which an inlet portis formed thereto, a chain cover combined with the pump housing andforming an outlet port with the pump housing, and a rotor including aninner gear and an outer gear, provided between the pump housing and thechain cover, and having a predetermined thickness and wherein a notchthat communicates with the outlet port may be formed in the pumphousing, and a slope may be formed between the end of the notch and theoutlet port.

The outlet port may include a center port having the same thickness ofthe rotor, a housing port formed to the pump housing and having a firstdepth and a cover port formed to the chain cover and having a seconddepth, and the sum of the first depth and the second depth may be 50% to60% of the rotor thickness.

The ratio of the first depth and the second depth may be 2:1 to 3:1.

The inner gear and the outer gear may form a plurality of pockets andthe formation position of the notch may be the angle corresponding tothe one pocket from the inlet port toward the outlet port and a positionthat is 5 degrees to 10 degrees apart based on the center of the rotor.

An end of the outlet port may be formed at 100 degrees to 120 degreesfrom the formation position of the notch based on the center of therotor.

A length of the notch may be 10 degrees to 15 degrees from the formationposition of the notch, based on the center of the rotor.

A depth of the notch may be 2% to 5% of the rotor thickness.

The slope may be formed in a 30 degree to 60 degree angle.

According to the hydraulic pump for a vehicle according to an exemplaryembodiment of the present invention, it is possible to reduce whinenoise by reducing pulsation pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a hydraulic pump for a vehicle accordingto an exemplary embodiment of the present invention.

FIG. 2 is a partial cross-sectional view along line A-A in FIG. 1.

FIG. 3 is a drawing excluding a chain cover of a hydraulic pump for avehicle according to an exemplary embodiment of the present invention.

FIG. 4 is a drawing excluding a rotor in FIG. 3.

FIG. 5 is a cross-sectional view of a hydraulic pump for a vehicleaccording to a modified exemplary embodiment of the present invention.

FIG. 6 is a graph comparing fine noise according to engine rpm.

The following reference numerals can be used in conjunction with thedrawings:

1: hydraulic pump for vehicle 10: pump housing 12: inlet port 30: rotor32: inner gear 34: outer gear 36: pocket 40: notch 45: slope 50: chaincover 70, 80: outlet port 72, 82: center port 74, 84: housing port 76,86: cover port 90: outlet

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following detailed description, only certain exemplaryembodiments of the present invention have been shown and described,simply by way of illustration.

As those skilled in the art would realize, the described embodiments maybe modified in various different ways, all without departing from thespirit or scope of the present invention.

Parts indicated by the same reference number throughout thespecification mean the same constituent elements.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity.

When a part of a layer, film, region, plate, etc. is said to be “above”another part, this includes not only directly above the other part butalso another part in the middle.

In contrast, when an element is referred to as being “directly on”another element, there are no intervening elements present.

Throughout the specification and the claims, unless explicitly describedto the contrary, the word “comprise” and variations such as “comprises”or “comprising” will be understood to imply the inclusion of statedelements but not the exclusion of any other elements.

Exemplary embodiments of the present invention will hereinafter bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a hydraulic pump for a vehicle accordingto an exemplary embodiment of the present invention.

A hydraulic pump 1 for a vehicle according to an exemplary embodiment ofthe present invention includes a pump housing 10 and a chain cover 50coupled to the pump housing 10.

FIG. 2 is a partial cross-sectional view along line A-A in FIG. 1, FIG.3 is a drawing excluding a chain cover of a hydraulic pump for a vehicleaccording to an exemplary embodiment of the present invention, and FIG.4 is a drawing excluding a rotor in FIG. 3.

Referring to FIG. 1 to FIG. 4, the hydraulic pump 1 for a vehicleaccording to an exemplary embodiment of the present invention includesan inner gear 32 and an outer gear 34, and includes a rotor 30 providedbetween the pump housing 10 and the chain cover 50.

An inlet port 12 through which oil is introduced is formed to the pumphousing 10, and the pump housing 10 and the chain cover 50 form anoutlet port 70 through which oil is exhausted.

The rotor 30 has a predetermined thickness T0, and the outlet port 70includes a center port 72 having the same thickness as the rotor 30, ahousing port 74 formed to the pump housing 10 and having a first depthT1 and a cover port 76 formed to the chain cover 50 and having a seconddepth T2.

The sum of the first depth T1 and the second depth T2 is 50% to 60% ofthe rotor thickness T0. When the sum of the first depth T1 and thesecond depth T2 is at least 50% of the rotor thickness T0, it isconfirmed through an experiment that high-speed whine noise is reduced.For example, a typical rotor thickness is about 18-25 mm, and when therotor thickness T0 is about 25 mm, the sum of the first depth T1 and thesecond depth T2 is formed to be at least 12.5 mm, thereby improvingwhine noise.

The ratio of the first depth T1 and the second depth T2 may be 2:1 to3:1. For example, if the second depth T2 is 3.6 mm, the first depth T1may be formed to about 90 mm.

The oil in the outlet port 70 is exhausted through outlet 90.

A notch 40 communicated with the outlet port 70 can be formed in thepump housing 10. It is confirmed through an experiment that the notch 40can suppress noise generation.

If the formation start point of the notch 40 is applied too close to theinlet port 12, the charging efficiency of hydraulic pump 1 may decreasein a high-speed section where the rotation speed of the hydraulic pump 1is high. On the other hand, if the formation start point of the notch 40is formed too far from the inlet port 12, the pressure is not relievedquickly and the noise, vibration, and harshness (NVH) characteristicsmay be disadvantageous.

The inner gear 32 and the outer gear 34 form a plurality of pockets 36,increase the oil pressure by the pockets 36, and the start position ofthe notch 40 may be determined by the pockets 36.

The formation position of the notch 40 is the angle corresponding to theone pocket 36 from the inlet port 12 toward the outlet port 70 and aposition (a) that is 5 degrees to 10 degrees apart based on the center Cof the rotor 30.

In FIG. 3, the number of the pockets 36 formed by the inner gear 32 andthe outer gear 34 is 7, the corresponding angle of each of the pockets36 is about 51 degrees (360/7), and the start position a of the notch 40is a position 5 to 10 degrees further away from the end of the inletport 12 than the angle of one pocket.

That is, in the case of the hydraulic pump according to an exemplaryembodiment of the present invention shown in the drawing, the formationstart position a of the notch 40 may be a position separated from theinlet port 12 by about 56-61 degrees.

If the formation start point of the notch 40 is too close to the inletport 12, the charging efficiency of the hydraulic pump 1 may decrease inthe high-speed section where the rotation speed of the hydraulic pump 1is high. On the other hand, if the formation start point of the notch 40is formed too far from the inlet port 12, the pressure in the pocket 36will not be relieved quickly and the NVH characteristics may bedeteriorated. In the case of the hydraulic pump according to anexemplary embodiment of the present invention, the start position a ofthe notch 40 is a position 5 to 10 degrees further away from the end ofthe inlet port 12 than the angle of one pocket, thus the chargingefficiency of the hydraulic pump 1 is maintained, and pressure in thepocket 36 can be smoothly relieved.

If a hydraulic pump has 10 pockets, the notch 40 can be started about41-46 degrees from the inlet port 12.

In consideration of high pressure formation and noise reduction, the endof the outlet port 70 can be formed at loo degrees to 120 degrees (γ)from the formation position of the notch 40 based on the center of therotor C.

A length L of the notch 40 may be 10 degrees to 15 degrees (β) from theformation position of the notch, based on the center of the rotor C. Inconsideration of the notch effect, the length (L) of the notch 40 can beformed at a level of 10-15% of the outlet port formation angle γ.

The depth of the notch can be 2% to 5% of the rotor thickness T0.

The capacity of the hydraulic pump is determined according to the rotorthickness. The notch depth can be proportional to the rotor thickness.However, if the notch thickness is too large, the notch effect can bereduced.

In an exemplary embodiment of the present invention, the depth T3 of thenotch 40 is set to 2% to 5% of the rotor thickness T0, so that the NVHcharacteristics can be improved. For example, when the rotor thicknessT0 is 25 mm, the minimum depth T3 of the notch 40 may be 0.5 mm.

A slope 45 is formed between the end of the notch 40 and the outlet port70, and the slope 45 may be formed to be inclined by 30 degrees to 60degrees.

The slope 45 connected to the notch 40 has a gentle slope, and theoutlet poll 70 is processed to deepen. If the angle of formation of theslope 45 is too rapid (e.g., 90 degrees), it may be disadvantageous fromthe NVH side due to rapid flow space expansion, and the slope angle ofthe slope 45 can be formed to be inclined by 30 degrees to 60 degrees.

FIG. 5 is a cross-sectional view of a hydraulic pump for a vehicleaccording to a modified exemplary embodiment of the present invention.

In describing the hydraulic pump for a vehicle according to a modifiedexemplary embodiment of the present invention of FIG. 5, theconfiguration and effects of the hydraulic pump for a vehicle accordingto an exemplary embodiment of the present invention are described aboveand the repetitive parts will be omitted.

An outlet port 80 of the hydraulic pump for a vehicle according to amodified exemplary embodiment of the present invention includes a centerport 82 having the same thickness T0 of the rotor 30, a housing port 84formed to the pump housing 10 and having a first depth T1 and a coverport 86 formed to the chain cover 50 and having a second depth T2. Thesum of the first depth T1 and the second depth T2 is 50% to 60% of therotor thickness T0.

Comparing to the hydraulic pump for a vehicle according to the exemplaryembodiment of the present invention, the hydraulic pump for a vehicleaccording to a modified exemplary embodiment of the present inventiondoes not include a notch, so that it does not have a notch effect, butits structure is simple and production cost can be reduced.

FIG. 6 is a graph comparing fine noise according to engine rpm.

Here, the comparative specification is a comparison between a hydraulicpump of the same capacity and a hydraulic pump having a discharge pumpof a different shape.

Compared to a general hydraulic pump (Base) for a vehicle, the hydraulicpump (A) for a vehicle according to a modified exemplary embodiment ofthe present invention that does not include a notch exhibits arelatively good noise characteristic. And it can be seen that thehydraulic pump (B) for a vehicle according to an exemplary embodiment ofthe present invention including a notch shows a relatively good noisecharacteristic compared to the hydraulic pump (A) for a vehicleaccording to a modified exemplary embodiment of the present invention.

As described above, the hydraulic pump for a vehicle according to theexemplary embodiment of the present invention can reduce pulsationpressure through shape change such as an outlet port, and thereby reducewhine noise.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments. On the contrary, it is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A hydraulic pump for a vehicle comprising: a pumphousing; an inlet port formed to the pump housing; a chain covercombined with the pump housing and forming an outlet port with the pumphousing; and a rotor provided between the pump housing and the chaincover and having a predetermined thickness, the rotor comprising aninner gear and an outer gear; wherein the outlet port includes a centerport having the same thickness as the rotor, a housing port formed tothe pump housing and having a first depth and a cover port formed to thechain cover and having a second depth; and wherein a sum of the firstdepth and the second depth is 50% to 60% of the thickness of the rotor.2. The hydraulic pump of claim 1, wherein a ratio of the first depth tothe second depth is between 2:1 and 3:1.
 3. The hydraulic pump of claim2, wherein the outlet port is formed inclined in a direction of theinlet port at an end.
 4. The hydraulic pump of claim 1, wherein: theinner gear and the outer gear form a plurality of pockets; a notch isconfigured to communicate with the outlet port and is formed in the pumphousing; and a formation position of the notch is an angle correspondingto the pocket from the inlet port toward the outlet port and a positionthat is 5 degrees to 10 degrees apart based on a center of the rotor. 5.The hydraulic pump of claim 4, wherein the end of the outlet port isformed at 100 degrees to 120 degrees from the formation position of thenotch based on the center of the rotor.
 6. The hydraulic pump of claim5, wherein: a slope is formed between an end of the notch and the outletport; and the slope is formed in a 30 degree to 60 degree angle.
 7. Thehydraulic pump of claim 4, wherein a length of the notch is 10 degreesto 15 degrees from the formation position of the notch based on thecenter of the rotor.
 8. The hydraulic pump of claim 4, wherein a depthof the notch is 2% to 5% of the thickness of the rotor.
 9. A hydraulicpump for a vehicle comprising: a pump housing; an inlet port formed tothe pump housing; a chain cover combined with the pump housing andforming an outlet port with the pump housing; and a rotor providedbetween the pump housing and the chain cover and having a predeterminedthickness, the rotor comprising an inner gear and an outer gear; whereina notch is configured to communicate with the outlet port and is formedin the pump housing; and wherein a slope is formed between an end of thenotch and the outlet port.
 10. The hydraulic pump of claim 9, wherein:the outlet port includes a center port having the same thickness as therotor, a housing port formed to the pump housing and having a firstdepth, and a cover port formed to the chain cover and having a seconddepth; and a sum of the first depth and the second depth is 50% to 60%of the thickness of the rotor.
 11. The hydraulic pump of claim 10,wherein a ratio of the first depth and the second depth is 2:1 to 3:1.12. The hydraulic pump of claim 10, wherein: the inner gear and theouter gear form a plurality of pockets; and a formation position of thenotch is an angle corresponding to the pocket from the inlet port towardthe outlet port and a position that is 5 degrees to 10 degrees apartbased on a center of the rotor.
 13. The hydraulic pump of claim 12,wherein an end of the outlet port is formed at loo degrees to 120degrees from the formation position of the notch based on the center ofthe rotor.
 14. The hydraulic pump of claim 13, wherein a length of thenotch is 10 degrees to 15 degrees from the formation position of thenotch based on the center of the rotor.
 15. The hydraulic pump of claim13, wherein a depth of the notch is 2% to 5% of the thickness of therotor.
 16. The hydraulic pump of claim 13, wherein the slope is formedin a 30 degree to 60 degree angle.
 17. A vehicle comprising: a vehiclebody; a pump housing for a hydraulic pump mounted in the vehicle body;an inlet port formed to the pump housing; a chain cover combined withthe pump housing and forming an outlet port with the pump housing; and arotor having a thickness and provided between the pump housing and thechain cover, the rotor comprising an inner gear and an outer gear;wherein the outlet port includes a center port having the same thicknessas the rotor, a housing port formed to the pump housing and having afirst depth, and a cover port formed to the chain cover and having asecond depth; and wherein a sum of the first depth and the second depthis 50% to 60% of the thickness of the rotor and a ratio of the firstdepth and the second depth is 2:1 to 3:1; wherein a notch configured tocommunicate with the outlet port is formed in the pump housing; andwherein a slope is formed between an end of the notch and the outletport.
 18. The vehicle of claim 17, wherein: the inner gear and the outergear form a plurality of pockets; and a formation position of the notchis an angle corresponding to the pocket from the inlet port toward theoutlet port and a position that is 5 degrees to 10 degrees apart basedon a center of the rotor.
 19. The vehicle of claim 18, wherein: an endof the outlet port is formed at loo degrees to 120 degrees from theformation position of the notch based on the center of the rotor; alength of the notch is 10 degrees to 15 degrees from the formationposition of the notch based on the center of the rotor; and a depth ofthe notch is 2% to 5% of the thickness of the rotor.
 20. The hydraulicpump of claim 19, wherein the slope is formed in a 30 degree to 60degree angle.